Development of molecularly imprinted polymers and its magnetic version for the extraction of fluoroquinolones from milk

The aim of the present study is to develop selective extracting materials applicable to a diversity of fluoroquinolones. A series of Molecularly Imprinted Materials (MIPs) were prepared in order to choose the nature of the monomer and that of the porogen together with its ratio with the cross-linker. A non-regulated quinolone, Levofloxacin, was used as a template to avoid false positive results in its application. The resulting MIPs were evaluated in MISPE experiments for Enrofloxacin. The polymer prepared using methyl acrylate (MA) as a monomer and MeOH/CHCl3 (1:1, v/v) as a porogen provided the desired selectivity. Concretely, 100 μL (1.1 mmol) of MA as a monomer, 1.30 mL (9.8 mmol) of EGDMA (ethyleneglycol dimethacrylate) as a cross-linker, 31 mg (0.19 mmol) of AIBN (2,2′-azobis(2-methylpropionitrile)) as an initiator, were mixed with 85 mg (0.24 mmol) of levofloxacin as a template and 4 mL of MeOH/CHCl3 (1:1, v/v) as a porogen. The obtained optimized composition was upgraded to magnetic molecularly imprinted polymers (MMIPs) to be used as a dispersive-SPE extracting materials in the analysis of fluoroquinolones in milk. The selectivity of the resulting material for several fluoroquinolones (enrofloxacin, ciprofloxacin, sarafloxacin and norfloxacin) was studied. Finally, the MMIP was tested against real quinolone positive milk samples to evaluate its applicability.